1. Field of the Invention
The present invention relates to a rotary magnetic head apparatus comprising a non-contact-type transmission apparatus for use in an information writing apparatus, such as a video tape recorder. More particularly, the present invention relates to a rotary magnetic head apparatus capable of reproducing signals of a plurality of recording tracks which are recorded on a tape-like information recording medium without depending on the arrangement of recording tracks in an information recording medium.
2. Description of the Related Art
Apparatuses for recording information onto a magnetic tape and reproducing information of a magnetic tape include video tape recorders, tape streamers, and the like. Such types of information writing apparatus comprise a rotary magnetic head apparatus for the purpose of recording a signal onto a magnetic tape and reproducing a signal of a magnetic tape.
The rotary magnetic head apparatus includes a rotary drum and a fixed drum, and the rotary drum includes a recording head and a reproduction head. The recording head is a head for recording a signal onto a magnetic tape, and the reproduction head is used to reproduce a signal recorded on a magnetic tape.
The rotary drum, which houses the recording head and the reproduction head, is rotated by the actuation of a motor with respect to the fixed drum, causing the recording head or the reproduction head to scan the magnetic tape, for example, by a helical scan method. Thus, information can be recorded onto a magnetic tape or information of a magnetic tape can be reproduced.
By adopting such a helical scan method, high-density recording of a signal onto a magnetic tape is made possible, and the relative speed between the magnetic tape and the magnetic head can be increased.
In the rotary magnetic head apparatus of a helical scan method, since the recording head and the reproduction head are housed inside the rotary drum, signals and power must be exchanged between this rotary drum and a fixed drum by a non-contact method; for example, in the case when a reproduction signal obtained from the reproduction head is transmitted from the rotary drum to the fixed drum, or when power for a circuit substrate is supplied from the fixed drum to the rotary drum.
In recent years, recording tracks which are recorded on a tape-like information recording medium are reproduced by what is commonly called a non-tracking method by setting a plurality of reproduction heads with respect to the rotary drum and by causing this plurality of reproduction heads to be rotated at a high speed. This non-tracking reproduction method is described below.
FIGS. 16A, 16B, and 16C show a tape-like information recording medium, for example, a magnetic tape TP such as a video tape. Recording tracks TC1 to TCn are formed in sequence at a high density on this magnetic tape TP. As shown in FIG. 16A, information has been recorded in adjacent recording tracks TC1 to TCn by +azimuth and xe2x88x92azimuth. In the tracking reproduction method which is conventionally used, a plurality of reproduction heads set in the rotary drum of the magnetic head apparatus reproduce the information of each recording track along the scan direction SC along each of the recording tracks TC1 to TCn.
However, in recent years, recording tracks have been getting increasingly narrower so that the recording density is increased, and the width of each recording track has been getting narrower. Therefore, in the case where each reproduction head accurately traces along the scan direction SC of the recording tracks by a tracking method and reproduces the information of each recording track as in the conventional art, the accuracy of the guide of the reproduction head, the error of the posture of the reproduction head in the rotary drum, and the like have a large influence, and reproduction with accuracy by a tracking method becomes very difficult.
Accordingly, a non-tracking reproduction method such as that described above has been proposed. For example, as shown in FIG. 16B, in the case where, as shown by the scan direction SC1 of a plurality of reproduction heads, when this scan direction SC is not parallel to the direction DD in which each recording track is formed and is inclined, that is, when the trace of the reproduction head during reproduction from the recording track is inclined, even though the area which is to be reproduced by a head of a particular azimuth is limited, in this method, by causing reproduction heads of a number, for example, twice that during recording to scan the recording tracks, it is possible for the adjacent reproduction heads with +azimuth and xe2x88x92azimuth of the rotary drum to trace all the recording tracks.
When, for example, a reproduction trace of a particular recorded track is taken note of, in the case where scanning at a twice-density is performed, the portions which cannot be read because the amplitude is small due to an inverse azimuth in the odd-number scans have the same azimuth at the same rotation phase of the next even-number scan, and the information of that recording track becomes capable of being always read. When this is repeated for some scans, data of one recording track is buried in sequence to a matrix, for example, like each of the recording areas RA1 and RA2 which form all the data of the recording tracks in such a manner as to be divided for some times, as shown in FIG. 16C, thereby the information ID of all the recording tracks can be reproduced. Such a method is a non-tracking reproduction method.
However, to realize such a non-tracking reproduction method, a plurality of reproduction heads, for example, four reproduction heads, are required. With an increase in the number of reproduction heads in this manner, in the rotary drum, the number of channels for signal transmission of the above-described rotary transformer set in the rotary magnetic head apparatus also increases to four. Therefore, the rotary drum and the fixed drum of the rotary magnetic head apparatus are forced to be enlarged, resulting in an increase in cost.
Accordingly, an object of the present invention, the achievement of which will solve the above-described problem, is to provide a rotary magnetic head apparatus capable of being formed into a smaller size in the case where signals of a plurality of recording tracks which are recorded on a tape-like information recording medium are reproduced by using a plurality of reproduction heads without depending on the arrangement of the recording tracks in the information recording medium.
To achieve the above-described object, according to the present invention, there is provided a rotary magnetic head apparatus which reproduces a signal of a plurality of recording tracks recorded on a tape-like information recording medium by using a plurality of reproduction heads without depending on the arrangement of the recording tracks in the information recording medium, the rotary magnetic head apparatus comprising: a transmission apparatus for transmitting power and signals between a rotor and a stator in a non-contact manner; a rotary drum having a rotor of a transmission apparatus and a plurality of reproduction heads; a fixed drum having a stator of the transmission apparatus; reproduction signal selection means for selecting a reproduction signal from each reproduction head and arranging the reproduction signal from each reproduction head in sequence; a rotor reproduction signal wiring section which is disposed in the rotor and to which a reproduction signal of each reproduction head is provided, which reproduction signal is transmitted from the reproduction signal selection means; and a stator reproduction signal wiring section, disposed in the stator, for receiving a reproduction signal in a non-contact manner from the rotor reproduction signal wiring section.
In the present invention, in the case where the signals of a plurality of recording tracks which are recorded on a tape-like information recording medium are reproduced by using a plurality of reproduction heads without depending on the arrangement of the recording tracks in the information recording medium, reproduction signal selection means selects a reproduction signal from each reproduction head and arranges the reproduction signal from each reproduction head.
Further, the rotor reproduction signal wiring section transmits a reproduction signal of each reproduction head transmitted from the reproduction signal selection means to the stator reproduction signal wiring section in a non-contact manner.
As a result, the rotary drum includes a plurality of reproduction heads. When a reproduction signal is obtained from each reproduction head, the reproduction signal selection means arranges a reproduction signal from these reproduction heads in sequence and provides the reproduction signals collectively to the rotor reproduction signal wiring section. Therefore, the rotor reproduction signal wiring section and the stator reproduction signal wiring section need to be provided for, for example, only one channel.
This makes it possible to greatly reduce the number of channels in the rotary magnetic head apparatus, and a smaller size of the rotary magnetic head apparatus is achieved.
The above and further objects, aspects and novel features of the invention will become more apparent from the following detailed description when read in connection with the accompanying drawings.